This may not be an amazingly complicated project, but it is a very elegant and fairly cheap way of building a UV oven for exposing PCBs. [aris] started with an IKEA FIRA cabinet. He basically left the framework as an empty shell and made a make shift top hinged door to enclose it. Mounted in the top is an array of 35 UV LEDs powered by an HP printer transformer. He did not have a timer circuit, instead he just watched the clock and unplugged it at the right time. You can see from his pictures that his results were quite good.
If you don’t want that piece of furniture taking up room, and don’t mind using a little more elbow grease, you could follow our directions on how to make your own single sided PCB. If money isn’t an issue either, you can always just get your PCBs laser etched.
Maybe my google skills aren’t very good, but I can’t see to find a source for these UV reactive PCB boards. Is there a special name for them?
Yes, Photo Etch Boards, they are recognisable by the black protective film, i have a question too, do UV leds work as well as a UV Flourecent Tube?
Yeah, I was kinda surprised by the idea of using uv leds.. I mean, it makes sense, and is kind of a ‘duh!’ moment for me.
Looking at his finished pcbs (check the posts sidebar) they look pretty good.
UV tubes are usually way more efficient than LEDs but you always can increase the exposure time or use more LEDs.
I personally use an old mercury-UV-lamp at appr. 40cm distance.
Earlier this year I made a similar lightbox using a 12″ record flight case and around 90 UV leds.
(Grainy publicly viewable pic on facebook here: http://www.facebook.com/photo.php?pid=36475041&l=07175&id=61204497 )
This method produces very good results, and mine only needed a gap of around 5cm before the emitted light became even (with the particular leds I used).
In the true style of building something to make something else, I first prototyped this point to point wiring all these leds which had been affixed in a 12″ square piece of wood. They then exposed the boards that now form the actual light box :)
I went down to the local glass supplier to get two panes of 12″ square glass cut to sandwich the mask and board.
There is also a 128×64 graphics LCD cut into the top that gives a nice display, and a rotary encoder switch (with button press) to give all of the input required.
All this was run off a 5v 2A (but not using all 2 amps!) wall mounted transformer.
-Andy
interesting idea. Get 100 or so ultra cheap UV 3mm LED’s off ebay, sand down using a jig sideways to 2mm and then glue them together side on and solder to the PCB. In theory you could expose an entire line in one go and the drive circuitry is as simple as a few 4017’s with a varying constant current on the power line.
You could probably also use SMD UV but this would be limiting.
-A
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